File Extension USF File Format Nintendo 64 Music File USF stands for Nintendo 64 Music File. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Broadside for MP3 pirates may kill indie labels Spotify goes Social Nintedno DS... DS Lite... DSi... DSi XL and now the 3DS?!?!?